This invention pertains to an interlock mechanism for use in a cabinet having two or more drawers, for preventing more than one drawer at a time from being opened.
In a file cabinet having two or more drawers, it is known to provide an interlock mechanism for preventing more than one drawer from being opened at a time, in order to prevent tipping of the cabinet. Representative interlock mechanisms are shown in Frederick et al U.S. Pat. No. 5,050,942; Scheerhorn U.S. Pat. No. 4,960,309; Pratzer U.S. Pat. No. 4,936,640; and Bowyer U.S. Pat. No. 4,884,853.
It is an object of the present invention to provide an interlock mechanism which is relatively simple in its construction and operation, and which provides positive interlocking action and reliable operation.
In accordance with the invention, a series of control members are mounted to the cabinet and arranged in an abutting end-to-end relationship relative to each other to define a joint between each pair of adjacent control members. The control members are preferably in the form of elongated axial rods. A series of pivotable members, in the form of levers, are mounted to the cabinet, with each lever being located adjacent to, and in alignment with, a joint between adjacent control members. Each pivotable lever is movable between a first position and a second position. In its first position, the pivotable lever engages the two control members at the joint therebetween to move the control members apart, and in its second position allows the two control members to remain in their abutting end-to-end relationship. Upon movement of one of the pivotable levers to its first position to move two adjacent control members apart, each joint between the remainder of the control members is moved out of alignment with its adjacent pivotable lever, so that the control members prevent movement of each of the remaining pivotable levers to its first position. An actuator member is mounted to each drawer, and each actuator member is engageable with one of the pivotable levers. Movement of a first one of the drawers to its open position causes engagement of the actuator member mounted to the first drawer with one of the pivotable levers, to move the pivotable lever from its second position to its first position. With this arrangement, movement of any other drawer to its open position is prevented due to engagement of the remaining pivotable levers with the control members. Moving the first drawer to its closed position results in engagement of the actuator member with the pivotable lever, to move the pivotable lever back to its second position, thus returning the control members to their original position in which a joint between adjacent control members is again located in alignment with its adjacent pivotable lever.
The control members are mounted for axial movement within a series of blocks mounted to the cabinet. In addition, each pivotable lever is also mounted to one of the blocks, with each block defining a pair of spaced walls between which one of the pivotable levers is mounted. Passages are formed in the spaced walls of each block for receiving the control members, to guide the control members for axial movement. Bias means, in the form of a pair of springs, is interconnected with the control members for urging facing ends of adjacent control members toward each other. Movement of each pivotable lever to its first position functions against the force of the springs, to move adjacent control members apart.
Each lever defines first and second arms disposed at an angle relative to each other. The first arm is located adjacent the joint between a pair of control members and is engageable by the actuator member upon movement of the drawer to its open position, to move the lever toward its first position. The second arm is engageable by the actuator member upon movement of the drawer to its closed position, to move the lever toward its second position. The first arm of the lever includes wedge structure for facilitating its interposition between facing ends of adjacent control members, to move the control members apart upon movement of the lever to its first position. A detent is associated with the first arm adjacent the wedge structure, for receiving the facing ends of adjacent control members when the lever is in its first position.
The invention further contemplates a method of preventing movement of more than one drawer of a multi-drawer cabinet to its open position, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.